NAOSITE: Nagasaki University's Academic Output SITE Title Effects of salinity, food level and temperature on the population growth on Noctiluca scintillans (Macarthy) Author(s) Lee, Jung Keun; Hirayama, Kazutsugu Citation 長崎大学水産学部研究報告, v.71, pp.163-168; 1992 Issue Date 1992-03 URL http://hdl.handle.net/10069/29863 Right This document is downloaded at: 2015-02-01T05:32:56Z http://naosite.lb.nagasaki-u.ac.jp Bull. Fac. Fish. Nagasaki Effects 163 Univ., No. 71 (1992) of salinity, population food level and temperature growth of Noctiluca scintillans Jung Keun LEE* and Kazutsugu The population tetrathelle cells/ml (Macartney). HIRAYAMA growth of Noctiluca scintillans was investigated, using Tetraselmis as food, at salinities ranging from 8.5-34‰, food levels from 1 x 10³-8 × 105 and temperatues from 5-32°C. Under every experimental twenty Noctiluca were grown individually to four days. analysis on the The specific growth of the population condition, in 1 or 3m1 of food suspensions rates were obtained ten to for three from the linear regression growth. Salinity : The specific growth rate was maximal at approximately 22‰, and decreased differentially with increasing or decreasing salinities. The lowest salinity for the minimal and continual growth was 14%o, but the sudden drop from 34‰ to 14‰ was lethal. Food Level : There was little growth at the food levels lower than 3 ×104 cells/ ml. At food levels between 3x 104and 3x 105cells/ml, the specific growth rate increased proportionally rate increased with increasing asymptotically. D ; 0.16) at 3 × 104 cells/ml, food levels. With further increases in food level, the The values of the specific growth rates were 0.03 (S. 0.74 (S. D ; 0.16) at 3 x 105 cells/ml at 8 ×105 cells/ml. Temperature : The specific growth rate was maximal around 23°C, and decreased differentially with increasing or decreasing temperatures. °C within a day. It grew at 5°C normally but slowly. Key words : A marine widely the protist distributed arctic.' growth Noctiluca from the caused frequently and tropical by reported from many In Japan, the Noctiluca almost annually between depending on the year frequency between factors In red tide and in the have and site." of occurrance, its growth and parts spring is to the plankton density world. its scintillans seas, its high rate ; Noctiluca tropics' It is one of the dominant temperate tides specific red been elucidate this information, experiments of are necessary and a stable Noctiluca * School Science culture Engineering. phytoflagellate 6) We found that in the prelimi- Tetraselmis for Noctiluca, Noctiluca culture ly in 1 or 3m1 of food suspensions lationship to in an organically in the tetrathelle and could using this In this study, we grew Noctiluca individual- experimental cultures and a stable tetrathelle; both and has a high food value the basic is a prerequsite. of Marine nary food organism. relationship of Noctiluca Graduate food suspension.' occurs autumn and the basic environmental experiments conducted medium' establish are not well known. vitro Tetraselmis been enriched All Noctiluca died at 32 of the In spite the scintillans; have and 0.81 (S. D ; 0.12) conditions between and under various clarified its population environmental factors. the growth reand 164 LEE and HiRAyAMA : Growth of Noctiluca Materials and Methods cycle. Sixty Noctiluca from each acclimated culture were tested in six salinities. ten Noctiluca ’ Al∂ctilzaca was collected with a plankton net in each salinity. Only those with active tentacle from Nomozaki Bay in Nagasaki Prefecture, movement were used. They were placed indi− southern Japan. It was maintained in culture vidually in 3ml of food suspensions of various on a diet of T. tetrathe〃e in about 100rnl of salinities, and their growth was monitored for GF/C filtered seaWater in petri−dishes. The three days. The food suspension was pre− む ロ culture was carrled out at 22−23 C ln fluorescent pared by adding lml of food culture (about 3× light((2−4)×1031ux)on 14L:10D light cycle. 105 cells/ml) to 2ml of filtered sea water of the , To deter面ne the s.pecific growth rate under same salinity, and its resultant concentration each experimental condition, ten to twenty was about 1×105 cells/ml. 〈ioctiluca were grown individually in l or 3ml b. lnfluence of salinity on the stoutness of of conditioned food suspensions for three to Noctiluca four days. This corresponded to ten to twenty Noctiluca were separatey cultured at 23, 28 cases. The experimental vessels used were and 320/oo for three weeks with sufficient food ’ Falcon multiplates(#3046 for 3ml experiment, and those with food vacuoles filled with algal #3047for lml experiment), which were com− food were used in the experiment. Thirty pletely sealed with vinyl tape to prevent IVoctiluca from each cultute were ’transferred evaporation. Linear regression analysis was into the wells of Falcon # rr!ultiplate, five in performed for each case using daily sensus each well containing 3ml of filtered sea water. counts, from which the following equation was The multiplates were placed on an electric deduced: shaker which reciprocated a distance of 1.5cm 1n Nt=kt十a at a rate of 155 times/min. ’Shaking was where Nt is the number of 1>Octiluca at time t, continued for periods of O, 2, 4, 8, 14, and 24 kis the specific growth rate, t is the time passed hours, and surviving Noctiluca were counted 24 in days and a is constant. When gametocytes7) hours after the start of shaking. were formed(0−3 cases out of ten), the cases were excluded from the analysis. As many 2. Food level specific growth rates as the valid cases were The algal food used for the experiments, obtained and the mean“k”with standard Ti tetrathelle, was grown in diluted filtered sea deviation, represented the specific growth rate water (220/oo) enriched with Erd−Schreiber medium under each experirnental condition. (1 : 1, volumetrically) to a concentration of 3× 1.Salinity were obtained by diluting the food culture with a.Specific growth rates the diluted filtered sea water. Plankton cell Noctiluca cultures were grown at four countings were done on the food culture using , 105 cells/ml. Various levels of food suspension salinities(17,22,27 and 34%・)for more than a a haemacytometer and the concentration was week. T. tetrathelle were grown in six salinities determined as the average of ten cell counts. (10,14,17,22,27,and 34%・), each in 100ml of Noctiluca were cultured with sufficient food. and ’ Erd−Schreiber medium in a 200ml flask. The those were used whose food−vacuoles were filled salinity of‡iltered sea water was measured with up with algal food. This experiment was run a digital salinometer(Tsurumi seiki, E−202), and at 230C, 220/oo and in dim light. The specific the desired salinities were obtained by diluting growth rate at each food level was obtained by filtered sea water with distilled water. The growing ten IVoctiluca individually in lml of food suspensions for four days. experiments were run at 23 C on 14L:10D light 165 Bull. Fac. Fish. Nagasaki Univ., No. 71 (1992) but growth curve diverged by food level from 3。Temperature the second day onwards. Thus, the data from peratures for one month, ranging from 5 to the second day on were used in the analysis. 280C, in a multi−chamber incubator accurate to±0.5 C. Food was given sufficiently. The (17 Oloo) algal food was also grown at the same tern− enriched with Erd−Schreiber medium (1:1, り acclimated at 28 C..The initial food levels were arranged at about 3×105 cells/ml. This ex− periment was conducted at 22%・on 12L:12D light cycle. The specific growth rate at each 〈roctiluca individually for three days in lml of O・2 o 一〇.2 一〇4 (22 o/.) 4 2 0 0 temperature was obtained by growing twenty O・4 0 一 and.at 32。C. Those tested at 32℃had been ︵z鑑,召︶ ”︵工︶田トくに エトタOαO 0一比一り国∩[の food, and tested at each acclimated temperature 嗣℃ whose food vacuoles were filled up with algal 2 o 。2 ㏄ α o0 02 peratures in diluted filtered sea water(22%・) volumetrically)・一Those〈⑩漉1%6αwere chosen.. / O・6 ヨ (27 Ol.) 一逓 Noctiluca were first acclimated at six tem− food suspensions. (34 01.) /1太 /i*i 04 O・2 ’ ,’ Fig. 1 shows the specific growth rates of Noctiluca at various salinities. Regardless of ’ Results o o de wh.Lu−一LLLLLL.L 10 20 30 10 20 30 SAUNITY (e/eo) the acclimated salinities. Nocliluca demonstrat一 ’ Fig. 1. The specific growth rates of N scintillans ed the highest specific growth rates at 220/oo, grown at various salinities. ln the paren− and the rates decreased differentially with theses are shown the salinities they were acclimated at before being transferred into increasing or decreasing salinities. The lowest various salinities. Vertical lines indicate salinity for the continual population growth was standard deviations. The open circle on ユ4%・,but the sudden drop from 34%・to 14%・was the x−axis signifies that all Noctiluca died at that salinity.(N;the number of八り6− lethal. ln lower than 100/oo S, Noctiluca was not tiluca:t; time in days: k; the specific viable. growth rate) Fig. 2 shows the survived number after ’ increased, the number of surviving Noctiluca decreased in all the groups and there were no 皿コ : 28脇 〔==コ:35eA・ 2 “」 40 黶j 〇 一一一一一一一一一一一一一一一一一一一一一一一一一一一 c 20 o 幽凶 」_一騨旧_; 」r_剛r騨」 一 」___■」 一 〇 2 4 8 14 and exposed to various food levels. The high experiment regardless of the initial food levels, 二2 vl .g di = Dい E 一,一 the growth of Noctiluca, which were fully fed growths were obtained in the first day of the 一 : 22 ont ゴOQ the groups in tolerance to the shaking shock. Fig. 3 is an example of the time course of Acclimated satinity 60 一﹂σ緕 tendencies to indicate any differences among αUロロΣ⊃Z ゴ]り 350/oo S, respectively. As the duration of shaking ︵0仁コσ£oも ミ醐い0‘一﹂Φζσ ω﹂‘“N︶ various lengths of shaking of three groups of ・Noctiluca which were acclimated at 22. 28 and 一 24 DURATION OF SHAKING ( hour) Fig. 2. The survival number of N. scintillans after various Iengths of shaking. 166 LEE and HiRAyAMA : Growth of IVoctiluca 8 //e ;≦§メ…≡i羅7) 02 l一振 う 30 /e i27・su 一 0 5 に国口Σ⊃Z ﹂﹂Uり e/ ./e(lo.11) 娼 ↓ 30 100 Q6 SaEinity:22 Oke @ 鱗 e/ エト≧6配OQ一﹂[O国巳の ●(30ゆ32) 22『陶S 論1︶ ︵Z潔 1・︵5山・く匡 23e c 20 十 α ︵ 200 乏 so+Z9 0 0 Fig. 5. 5 10 15 20 25 so TEMPERATURE (eC) The specific growth rates of N scintillans grown at various temperatures. The num− bers next to the vertical lines’ represent the (丁) food levels (cells ×10‘ /ml) at the start and end of the experiment. The explanation 10 o Fig. 3. The growth curves of N. scintillans which were exposed to various food levels 104and 3×105 cells/m1, the specific growth rate immediately after being fully fed. The numbers in the parentheses indicate the increased gradually with increasing food levels, food levels (cells ×10‘/ml) at the start and but it increased asymptotically with further end of the experiment. For the food levels increase in food level. The specific growth rateS lower than 1×10‘ cells/ml, only the initial (k)were O.03(S. D;0.16)at 3×104 cells/ml,0.74 (S.D;0.16)at 3×105 cells/ml and O.81(S. D;0.12) at 8×105 cells/ml. Fig.5shows the specific growth rates of 〈loctil勿ca at various temperatures. The rate was む highest around 23 C, and decreased differential− 十 十 エ↑≧O¢OO一﹂一〇国住の O・2 十 ︵ 0 0 O・4 00 6 論︶杢︶ω↑く ︵Zメー− 23ec 22 9ke S ー ーエー food levels are given. LO of marks is given in Fig. 1. 1 2 3 4 DAYS AFTER INOCULAT!ON ly with increasing or decreasing temperatures. む 八「octiluca grew at 5 C, but all died within a day at、31−32 C. The food levels during the ex− periment were between about 3×105 cells/ml and about 5×105 cells/ml. o 一〇一2 1 10 100 Discussion FOOD LEVEL (cettsxlo4mt−t) Fig. 4. The specific growth rates of IV. scintillans grown at various food levels. The ex− planation of marks is given in Fig. 1. The results in Fig. 1 demonstrate that Noctilzaca is adaptable to wide range of salinities when the salinity change is slow and gradual, The growths of algal food during the experi− and that the most suitable salinity for growth ment under these experimental conditions were of IVoctiluca is around 220/oo. The growth of less than 200/o of the initial food levels. algal food during the salinity experiment is Fig. 4 shows the relationship between the considered not to affect the results obtained specific growth rate of Noctiluca and food level. because T. tetrathelle is euryhaline and grows There was little ,growth of Noctiluca at the food at a similar rate in salinities ranging from 10 level lower than 3×104 cells/ml. Between 3× to 340/oo.8’ The salinity at which the highest 167 Bull. Fac. Fish. Nagasaki Univ., No.71 (1992) growth rate is found is not necessarily the be one of the causes of the disappearance. optimal salinity for population increase. The However, a tropical strain of green八ioctiluca, physiological stoutness (i. e., tolerance to the which contains flagellated symbionts, grows well adverse environment)must be considered as around 300C.i) This indicates that the tolerance well. The results in Fig.2show that〈loctilu ca to high temperature may be different by strain. grown at 22%・for three weeks is as phys− Though八ioctiluca has a potential to grow iologically stout as those grown at higher salini− at a speed of more than one division a day, it ties. From these results, it can be concluded is highly improbable that such a high growth that approximately 22%・is the optimal salinity rate will be found in nature because the most for ノ>bctiluCa. favorable environments (i. e., 220/oo S, 220C and Because the results of the salinity ex− plenty of food) are hardly met at the same time. periment showed that the optimal salinity for The high salinity will always suppress the full ノ>Octiluca is 22%・, the food level experiment was growth of Noctiluca, and it would be a rare case carried out at 22%・, The results in Fig.3show for them to meet even the threshold level of that the growth of algal food during the ex− living food, even during the spring time when periment was suppressed enough under these the phytoplankton flourish. Occasionally, the experirnental conditions not to influence the food organisms appear in high density, but results obtained. The relationship between the this state doesn’t last long. ln this respect, the specific growth rate of Noctiluca and food level bloom of Noctiluca seems to be a visual drew a typical S−shaped growth curve(Fig.4). phenomenon which is not necessarily related The maximal rate shows that, with enough food to the sudden growth of it. and a suitable environment 1>Octiluca can divide With respect to the maintenance and more than twice a day. However, the fact that increase of the Noctiluca population, the rela− 〈loctiluca started to grow around 3×104 cells/ で tive importance of its tolerance to adverse ml indicates that 1>Octiluca in nature may be in environments and its ability to use non−living serious food deficient state as far as living food organic matter as food source have yet to be is concerned. This food deficient state seem studied. , to be rectified by phagotrophy9)or possibly by References using dissolved organ!c matter4), but the extent of rectification has yet to be studied. The results in Fig.5show thatハloctiluca 1) Sweeney, B. M. (1971):Laboratory studies is eurythermal and the optimal temperature is of a green Noctiuca from New Guinea. J. approximately 23 C. Based on the results of phycol., 7, 53−58. food level experiments, this experiment was 2) Tibbs, J. F. (1967): On some planktonic done at the high food levels where the growth protozoa taken from the track of drift rate of Noctiluca increases asymptotically in station ARLIS 1. 1960−1961. Arctic, 20, 247− order that the varying food levels during the 254. experiment would not affect the results ob一 3) Takayama, H. (1984): Red tide organisms tained. Noctiluca grows normally at 5 C to see occurring in coastal waters of Hiroshima the fact that they contained as much food in prefecture−II: IVoctiluca scintillans (Macart− their food vacuoles as those at higher ney).“ Bull. Hiroshima Fish. Res. Lab., 14, temperatures. In the temperate sea,〈loctiluca 25−29. suddenly disappears in the summer season.10) 4) McGinn, M. P. (1962) : Axenic cultivation of From the fact that all〈loctiluca died at 32。C, Noctiluca scintillans. J. Protozool., 16 the lethal effect of high temperature seems to (suppl.), 13. 168 LEE and HIRAYAMA : Growth Saibai Giken, 14 (2), 85-110. 5) Nawata, T., and T. Sibaoka (1976): Ionic composition and pH of the vacuolar sap in marine dinoflagellate of Noctiluca 9) Kimor, B. (1981) : The role of phagotrophic Noctiluca. Plant Cell dinoflagellates in marine ecosystems. 15. European marine biology symposium. Kiel Physiol. 17, 265-272. 6) Takayama, H. (1977): Culture of Noctiluca (GRG) : lower organisms and their role in the food web. Rheinheimer, G. ; Fluegel, scintillans (Macartney).* Bull. Plankton Soc. H. Lenz, Z. Zeitschel, B. (eds.). Institut fuer Meereskunde, Kiel (FRG). 164-173. Jap., 24 (2), 159-162. 7) Zingmark, R. G. (1970): Sexual reproduction in the dinoflagellate Noctiluca miliaris 10) Uhlig, G. and G. Sahling (1982): Rhythms suriray. J. Phycol. 6, 122-126. 8) Okauchi, and distributional M. N. (1988) : The mass culture and food value of Tetraselmis tetrathelle.** 夜光虫 (Notiluca scintillans) 餌 料 密 度,温 李 Tetraselmistetrathelleを 濁 液 に 入 れ,い 比 増 殖 率 を 算 出 し,そ in Noctiluca の 増 殖 と塩 分, 度 との 関 係 正 根 ・平 山 餌 料 と し て,10-20尾 ろ い ろ の 飼 育 条 件 で 飼 育 し,そ phenomena miliaris. Ann. Inst. oceanogr., Paris, 58 (S), 277-284. 和次 の 夜 光 虫 を1尾 ず つ 個 別 に1-3m1の の 増 殖 を 調 べ た 。3-4日 餌料懸 間 の増 殖 経 過 か ら 日間 の平 均値 を求 めた 。 塩 分 (8.5-34‰) : 22‰ で 最 大 の比 増 殖 率 が得 られ,そ れ 以 上,そ れ 以 下 の塩 分 で は塩 分 の増 加 あ る い は減 少 と と もに比 増殖 率 は減 少 した 。 が, 以上の塩分 では安定的な増殖がみ られた 34‰ の海水か ら直接 14‰ の海 水 に移 す と死 滅 した 。 餌 料 密 度(1×10ウ-8×105ce11s/ml):餌 ん ど 増 殖 し な か っ た 。3×IO4cells/mlか に 比 増 殖 率 も増 加 し た が,そ 殖率の値 (22‰, 23C) 料 密 度 が3×104cells/ml以 ら3×105cells/mlの 温 度(5-32℃):最 れ 以上 の餌 料 密度 で は 比増 殖 率 の増加 の割 合 は低 下 した。 比増 大 比 増 殖 率 は 約23℃ あっ た。 で え られ,そ の 高 温 で は す べ て の 夜 光 虫 は1日 した。 * : in Japanese ** : in Japanese 光虫はほと は3×104cells/mlで0.03/日(S.D.:0.16),3×105cells/mlで0.74 (S.D;0.16),8×105cells/mlで0.81/日(S.D.;0.12)で 少 し た 。32℃ 下 で は,夜 間 で は餌 料密 度 の増 加 と とも with English summary れ 以 上,ま た はそ れ 以 下 の温 度 で は 減 以 内 に 死 滅 し た が,5℃ の 低 温 で も正 常 に 増 殖
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